As the complexity of computer programs has grown and as their capabilities have expanded, it has become increasingly difficult to provide user interfaces sufficiently simple and flexible to be used by inexpert non-programmer users. The most common solution to this problem has been to provide multi-layer menus to guide in the selection of specific capabilities of these software systems. That is, the inexpert user is presented with a menu from which a selection is made. Each menu selection triggers the presentation of the next lower level menu until, at the lowest level menu, the menu selection triggers the execution of an appropriate process to carry out the specific program capability identified on the menu entry.
The above-described menu-driven user interface has the great advantage of allowing inexpert users to control and use very powerful and very complex software systems. One problem with such systems, however, is the rigidity of the menu system itself. Such menu systems tend to be complex and interrelated and hence can usually be modified or updated only by highly qualified computer programmers. Moreover, the addition, deletion or modification of the underlying capabilities of the software system is not easily accompanied by the appropriate changes in the menu system.
Because of this tendency towards rigidity in the menu system, different requirements of different users are not possible to accommodate economically. Menu-driven systems therefore tend to be general enough for all possible intended users and therefore somewhat inappropriate for all actual users with different specific requirements.